Wood-based solar thermal devices, and methods for fabrication and use thereof

Abstract

Solar thermal devices are formed from a block of wood, where the natural cell lumens of the wood form an interconnected network that transports fluid or material therein. The block of wood can be modified to increase absorption of solar radiation. Combining the solar absorption effects with the natural transport network can be used for various applications. In some embodiments, heating of the modified block of wood by insolation can be used to evaporate a fluid, for example, evaporating water for extraction, distillation, or desalination. In other embodiments, heating of the modified block of wood by insolation can be used to change transport properties of a material to allow it to be transported in the interconnected network, for example, heating crude oil to adsorb the oil within the block of wood.

1 . A method comprising:
 (a) cutting a block of natural or lignin-reduced wood to have a first surface, a second surface opposite the first surface, and an internal fluidic transport network comprised of microstructures of natural wood between the first and second surfaces;   (b) forming a solar absorption layer on at least the first surface of the wood block; and   (c) forming a plurality of artificial holes extending from the first surface to the second surface.   
     
     
         2 . The method of  claim 1 , wherein (c) comprises forming each artificial hole to have a diameter of 100 μm to 5 mm. 
     
     
         3 . The method of  claim 1 , wherein:
 the cutting of (a) is such that the wood block has cellulose-based lumen extending along a tree growth direction that is parallel to at least one of the first and second surfaces, or   the cutting of (a) is such that the wood block has cellulose-based lumen extending along a tree growth direction that is at a non-zero angle with respect to at least one of the first and second surfaces.   
     
     
         4 . The method of  claim 1 , wherein (b) comprises carbonizing at least the first surface of the wood block to form the solar absorption layer. 
     
     
         5 . The method of  claim 1 , wherein the solar absorption layer of (b) comprises a coating of nanoparticles, nanowires, graphene, graphene oxide, reduced graphene oxide, graphite, single walled carbon nanotubes, double walled carbon nanotubes, multiwalled carbon nanotubes, polyaniline, carbon black, amorphous carbon, hard carbon, soft carbon, metal oxide, or any combination thereof. 
     
     
         6 . The method of  claim 5 , wherein the nanoparticles comprise plasmonic metallic nanoparticles. 
     
     
         7 . The method of  claim 1 , further comprising, prior to (b), chemically-treating the wood so as to remove at least some lignin therefrom. 
     
     
         8 . The method of  claim 1 , further comprising:
 (d) after (c), contacting the second surface of the wood block with a fluid while exposing the first surface to insolation,   wherein, during (d), the wood block conveys the fluid from the second surface to the first surface via capillary action and/or nano-cavitation effects in the internal fluidic transport network, and the exposing to insolation is effective to evaporate at least some of the fluid at the first surface.   
     
     
         9 . A method comprising:
 (a) providing a wood block having a first surface, a second surface opposite the first surface, a solar absorption layer formed at the first surface, and a fluidic transport network formed by microstructures of natural wood between the first and second surfaces and by at least one of:
 a plurality of natural lumens extending from the first surface to the second surface, each natural lumen having a diameter greater than or equal to 100 μm; and 
 a plurality of artificial holes extending from the first surface to the second surface, each artificial hole having a diameter of 100 μm to 5 mm; 
   (b) placing the second surface of the natural wood block in contact with a fluid; and   (c) after (b), exposing the first surface to insolation,   wherein the wood block pumps fluid from the second surface to the first surface via capillary action and/or nano-cavitation effects in the fluidic transport network, and   fluid from the fluidic transport network and/or from the first surface returns to the second surface via the plurality of natural lumens and/or artificial holes.   
     
     
         10 . The method of  claim 9 , wherein the natural wood comprises balsa, elm, or padauk. 
     
     
         11 . The method of  claim 9 , wherein the fluid contains salt, and during transport of the fluid between the first and second surfaces during (c), a salinity is lower in the artificial holes and/or natural lumens than other portions of the fluidic transport network. 
     
     
         12 . The method of  claim 9 , further comprising:
 (d) condensing vapor emanating from the first surface back,   wherein the fluid comprises salt water, and the condensing of (d) yields desalinated water.   
     
     
         13 . The method of  claim 12 , wherein during hours of continuous performance of (c), no salt deposits are formed on the first surface. 
     
     
         14 . The method of  claim 9 , wherein the second surface is placed in a body of the fluid or in a ground containing the fluid.